﻿//
// (C) Copyright 2009 Irantha Suwandarathna (iranthas@hotmail.com)
// All rights reserved.
//

/* Copyright (c) 2001-2008, The HSQL Development Group
 * All rights reserved.
 *
 * Redistribution and use _in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions _in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer _in the documentation
 * and/or other materials provided with the distribution.
 *
 * Neither the name of the HSQL Development Group nor the names of its
 * contributors may be used to endorse or promote products derived from this
 * software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL HSQL DEVELOPMENT GROUP, HSQLDB.ORG,
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;
using EffiProz.Core.Lib;
using EffiProz.Core.Store;
using EffiProz.Core.Errors;
using EffiProz.Core.Results;
using EffiProz.Core.Navigators;
using EffiProz.Core.DataTypes;

namespace EffiProz.Core.Persist
{
    public class LobStoreRAFile : LobStore
    {
        int lobBlockSize = 1024 * 32;
        FileStream file;
        Database database;

        public LobStoreRAFile(Database database, int lobBlockSize)
        {

            this.lobBlockSize = lobBlockSize;
            this.database = database;

            try
            {
                String name = database.getPath() + ".lobs";
                bool exists =
                    database.logger.getFileAccess().IsStreamElement(name);

                if (exists)
                {
                    openFile();
                }
            }
            catch (Exception t)
            {
                throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
            }
        }

        private void openFile()
        {

            try
            {
                String name = database.getPath() + ".lobs";
                bool rdy = database.isReadOnly();

                file = new FileStream(name, FileMode.OpenOrCreate, rdy ? FileAccess.Read
                                                           : FileAccess.ReadWrite);
            }
            catch (Exception t)
            {
                throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
            }
        }

        public byte[] getBlockBytes(int blockAddress, int blockCount)
        {

            if (file == null)
            {
                throw Error.error(ErrorCode.FILE_IO_ERROR);
            }

            try
            {
                long address = (long)blockAddress * lobBlockSize;
                int count = blockCount * lobBlockSize;
                byte[] dataBytes = new byte[count];

                file.Seek(address, SeekOrigin.Begin);
                file.Read(dataBytes, 0, count);

                return dataBytes;
            }
            catch (Exception t)
            {
                throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
            }
        }

        public void setBlockBytes(byte[] dataBytes, int blockAddress,
                                  int blockCount)
        {

            if (file == null)
            {
                openFile();
            }

            try
            {
                long address = (long)blockAddress * lobBlockSize;
                int count = blockCount * lobBlockSize;

                file.Seek(address, SeekOrigin.Begin);
                file.Write(dataBytes, 0, count);
            }
            catch (Exception t)
            {
                throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
            }
        }

        public void close()
        {

            try
            {
                if (file != null)
                {
                    file.Close();
                }
            }
            catch (Exception t)
            {
                throw Error.error(ErrorCode.DATA_FILE_ERROR, t);
            }
        }
    }
}
